Hi !
I'm new with arduino! i have recently bought an Elegoo Mega2560 R3.
I have many communication pins :
How can i send a string of characters to my PC (RS232) ?
What hardware i will need? and what code i will need?
Thank you.
Best regards!
MisterEmine:
How can i send a string of characters to my PC (RS232) ?
What hardware i will need? and what code i will need?
Any reason you can't use USB. No extra hardware needed for that.
TX0/TX0 is internally connected to the USB<>Serial chip.
It's not just for uploading new sketches, but can also be used for serial comms.
Serial.print("send a string to the PC"); // prints the string on the serial monitor of the PC
Leo..
If you want to not use the USB or want to use tx1 etc , then you need a converter to raise the voltage levels to those of RS232. You can buy TTL
To RS232 converters of use a MAX232 chip
Hi !
I can't use USB connector, because my computer have only 1 free RS232 connector (DB9).
So i will buy TTL to RS232 converters of use a MAX232 chip. Thank you.
Arduino <==> TTL to RS232 Converters <==> RS232 (DB9 Connector) <==> Computer
Any one can give me a code for sending the following string of characters?
<25FK;AE;01>
Can some one give a link to the TTL to RS232 Converters using MAX232 Chip?
Thank you 
MisterEmine:
I can't use USB connector, because my computer have only 1 free RS232 connector (DB9).
Absolute nonsense! I cannot believe you have a PC with no USB ports. You must have USB ports. 
Hie ye down to the local "dollar shop" and get a USB hub. Plug the keyboard and mouse into the hub - which is extremely convenient whenever you need to switch both keyboard and mouse to a different computer - and plug your Arduino into the free USB port.
I advise this rather than plugging the Arduino into the hub unless it is a powered hub. Keyboards and mice take very little current, so can be shared on a non-powered hub. If you had one of the better Dell keyboards, you would be able to plug the mouse into the keyboard itself anyway. 
MisterEmine:
...my computer have only 1 free RS232 connector (DB9).
386SX-25 with Win3.1 ?
So you don't have USB connectors on your PC?
How do you upload a sketch...
If you don't have enough USB sockets, can't you use a USB hub?
Leo..
I know i can use USB hub, but i don't have any USB ports.
It's an industrial terminal PC, and i don't have any USB ports, that's why i'm using the RS232 DB9 connector.
Wawa:
386SX-25 with Win3.1 ?
Closer to the truth, apparently!
Wawa:
So you don't have USB connectors on your PC?
How do you upload a sketch...
Apparently using a different computer.
I do see the point now - he is developing a device on a modern computer in order to interface to a piece of old industrial equipment.
Try Alice!
Paul__B:
Closer to the truth, apparently!
Apparently using a different computer.I do see the point now - he is developing a device on a modern computer in order to interface to a piece of old industrial equipment.
Try Alice!
Thank you for the url link i apreciate it!
and now ,can some one give me a code for sending the following string of characters?
<25FK;AE;01>
Thank you
MisterEmine:
Thank you for the url link
Note that you will need to determine whether you need a "straight" or "crossover" cable.
MisterEmine:
and now ,can some one give me a code for sending the following string of characters?
<25FK;AE;01>
Including the angle brackets or just the part in between?
Paul__B:
Note that you will need to determine whether you need a "straight" or "crossover" cable.
Including the angle brackets or just the part in between?
I will need a programm to send this string of characters including the angle brackets :
<25FK;AE;01>
Thank you i will check if it's straight or crossover cable.
Thank you very much.
void setup(){
Serial.begin(WhatEverBaudrateYouNeed);
Serial.print("<25FK;AE;01>")
}
void loop(){
}
Using a Mega for that is a bit overkill but okay.
septillion:
void setup(){
Serial.begin(WhatEverBaudrateYouNeed);
Serial.print("<25FK;AE;01>")
}
void loop(){
}
Using a Mega for that is a bit overkill but okay.
So what king of arduino you advice me to take?
A Nano or a Pro Mini would do the job fine
I have another problem,
When i upload the programm into my arduino mega2560 R3, this code work fine,
String a = "<25FK;AE;01>";
String b = "<25FK;AE;06>";
void setup()
{
Serial.begin(9600);
}
void loop()
{
Serial.print(a);
delay(1000);
Serial.print(a);
delay(1000);
}
but when i unplug the usb connector all the programm is lost.
It's normal? i need to save the programm in my arduino and not upload the programm evey time i power on this arduino.
That's simply impossible So what makes you think it behaves like that?
Also made some changes to the code
const char CommandA[] = "<25FK;AE;01>";
const char CommandB[] = "<25FK;AE;06>";
const unsigned int Baudrate = 9600;
const unsigned int SendDelay = 1000;
void setup()
{
Serial.begin(Baudrate);
}
void loop()
{
Serial.print(CommandA);
delay(SendDelay);
Serial.print(CommandB);
delay(SendDelay);
}
And do you really want to send those commands alternating infinite?
I wouldn't want to change your code but perhaps a blinking LED might help the OP troubleshooting
Like this?
const char CommandA[] = "<25FK;AE;01>";
const char CommandB[] = "<25FK;AE;06>";
const unsigned int Baudrate = 9600;
const unsigned int SendDelay = 1000;
void setup()
{
Serial.begin(Baudrate);
pinMode(LED_BUILTIN, OUTPUT);
}
void loop()
{
digitalWrite(LED_BUILTIN, HIGH);
Serial.print(CommandA);
delay(SendDelay);
digitalWrite(LED_BUILTIN, LOW);
Serial.print(CommandB);
delay(SendDelay);
}
MisterEmine:
I have another problem,
When i upload the programm into my arduino mega2560 R3, this code work fine,but when i unplug the usb connector all the programm is lost.
It's normal? i need to save the programm in my arduino and not upload the programm evey time i power on this arduino.
How do you know it is lost?
What is powering the mega when you disconnect the USB port?
Thanks.. Tom...
I do see the point now..
Thats what happens when the whole setup/problem is not explained fully from the beginning..
It takes 8 posts/replies just to figure out whats really going on...